TITLE OF THE INVENTION
COAL BRIQUETTES AND METHOD FOR MANUFACTURING THE SAME
CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority to and the benefit 5 it of Korean Patent
Application No. 10-2014-0189077 filed in the Korean Intellectual Property Office
on December 24, 2014, the entire contents of which are incorporated herein by
reference.
10 BACKGROUND OF THE INVENTION
(a) Field of the Invention
The present invention relates to coal briquettes and a method for
manufacturing the same. More particularly, the present invention relates to
coal briquettes that are not easily differentiated when being coated with an
15 endothermic material and then charged into a melter-gasifier, and a method for
manufacturing the same.
(b) Description of the Related Art
In an iron ore melting reduction technology, a reduction furnace for
reducing iron ore and a melter-gasifier for melting reduced iron ore are used.
20 In the case of melting iron ore in the melter-gasifier, the melter-gasifier is
charged with coal briquettes as a heat source for melting iron ore. Here,
reduced iron is melted in the melter-gasifier and thus converted to molten iron
and slag and then discharged to the outside. The coal briquettes charged into
the melter-gasifier form a coal-packed bed. Oxygen is blown into the melter2
gasifier through a tuyere and burns the coal-packed bed such that a combustion
gas is generated. The combustion gas moves upward through the coalpacked
bed and is then converted to a high-temperature reduction gas. The
high-temperature reduction gas is discharged to the outside of the meltergasifier
and is thus supplied as a reduction gas to a reduction 5 n furnace.
The coal briquettes charged into melter-gasifier can be easily
differentiated while meeting high-temperature gas existing in an upper portion of
the melter-gasifier. When the coal briquettes are high-temperature
differentiated, combustion heat required for melting of reduced iron provided
10 below the melter-gasifier cannot be provided. Thus, since a large amount of
coal briquettes is used, fuel cost is increased and fine ore in the melter-gasifier
is increased so that ventilation in the melter-gasifier is deteriorated.
The above information disclosed in this Background section is only for
enhancement of understanding of the background of the invention and therefore
15 it may contain information that does not form the prior art that is already known
in this country to a person of ordinary skill in the art.
SUMMARY OF THE INVENTION
The present invention has been made in an effort to provide coal
briquettes that cannot be easily differentiated when being charged into a melter20
gasifier. Further, a method for manufacturing the above-stated coal briquette
is provided.
The present invention relates to a method for manufacturing coal
briquettes in a molten iron manufacturing device including a melter-gasifier into
which reduced iron is charged and a reduction furnace connected to the melter3
gasifier and providing reduced iron, the coal briquettes being charged into a
dome portion of the melter-gasifier and rapidly heated. The method includes:
providing a mixture of raw coal and a binder; coating an endothermic material to
the surface of a pair of molding rolls applied to mold the mixture; and providing
coal briquettes coated with the endothermic material by charging 5 ing the mixture
between the pair of molding rolls and compression-molding the mixture with the
pair of molding rolls.
In the coating of the endothermic material, the endothermic material
may be selected from a group consisting of a metal hydroxide, limestone, and
10 dolomite.
The amount of endothermic material may be 3 wt% to 15 wt% of the
coal briquettes, and specifically, the amount of the endothermic material may be
4 wt% to 8 wt% of the coal briquettes.
In the providing of the mixture, the binder may be a material selected
15 from a group consisting of molasses, raw sugar, cellulose, starch, and bitumen
In the providing of the mixture, the amount of powdered coal having a
grain diameter of 5 mm or less included in the raw coal may be 90 wt% to 100
wt%.
In the coating of the endothermic material, the surface of the pair of
20 molding rolls may be maintained at room temperature.
In the providing of the mixture, the mixture may include a binder at 3
wt% to 15 wt% and raw coal as the remaining portion of the mixture..
In coal briquettes provided to a molten iron manufacturing device
including a melter-gasifier to which reduced iron is charged and a reduction
4
furnace connected to the melter-gasifier and providing reduced iron, the coal
briquettes are charged into a dome portion of the melter-gasifier and rapidly
heated therein, and include a mixture of raw coal and a binder; and an
endothermic material coated to the mixture.
The endothermic material may be a material selected 5 lected from a group
consisting of a metal hydroxide, limestone, and dolomite.
the amount of endothermic material may be the amount of endothermic
material is 3 wt% to 15 wt% of the coal briquettes, and specifically, the amount
of endothermic material may be 4 wt% to 8 wt% of the coal briquettes.
10 The mixture may include a binder at 3 wt% to 15 wt% and raw coal as
the remaining portion of the mixture.
Since coal briquettes coated with the endothermic material are charged
into the melter-gasifier, the coal briquettes cannot be easily differentiated in the
melter-gasifier. Accordingly, combustion heat for melting of reduced iron can
15 be sufficiently provided, thereby saving fuel cost. Further, ventilation in the
melter-gasifier can be improved.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic flowchart of a method for manufacturing coal
briquettes according to an exemplary embodiment of the present invention.
20 FIG. 2 is a photo of a surface shape of coal briquettes where char is
formed from various high-temperature gasses.
FIG. 3 is a schematic partial perspective view of a molding device that
manufactures the coal briquettes of the method of FIG. 1.
FIG. 4 is a schematic cross-sectional view of the molding device of FIG.
5
3, taken along the line IV-IV.
FIG. 5 is a schematic view of a molten iron manufacturing apparatus
using the coal briquettes manufactured in the method of FIG. 1.
FIG. 6 is a schematic view of another molten iron manufacturing
apparatus using the coal briquettes manufactured 5 anufactured in the method of FIG. 1.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Terms such as first, second, and third are used to illustrate various
portions, components, regions, layers, and/or sections, but not to limit them.
These terms are used to discriminate the portions, components, regions, layers,
10 or sections from other portions, components, regions, layers, or sections.
Therefore, a first portion, component, region, layer, or section as described
below may be a second portion, component, region, layer, or section within the
scope of the present invention.
It is to be understood that the terminology used therein is only for the
15 purpose of describing particular embodiments and is not intended to be limiting.
It must be noted that, as used in the specification and the appended claims, the
singular forms include plural references unless the context clearly dictates
otherwise. It will be further understood that the terms "comprises" and/or
"comprising," when used in this specification, specify the presence of stated
20 properties, regions, integers, steps, operations, elements, and/or components,
but do not preclude the presence or addition of one or more other properties,
regions, integers, steps, operations, elements, and/or components thereof.
Unless it is mentioned otherwise, all terms including technical terms and
scientific terms used herein have the same meaning as the meaning generally
6
understood by a person with ordinary skill in the art to which the present
invention belongs. The terminologies that are defined previously are further
understood to have the meanings that coincide with related technical
documents and the contents that are currently disclosed, but are not to be
interpreted as having ideal or very official meanings unless defined otherw5 ise.
The present invention will be described more fully hereinafter with
reference to the accompanying drawings, in which exemplary embodiments of
the invention are shown. As those skilled in the art would realize, the
described embodiments may be modified in various different ways, all without
10 departing from the spirit or scope of the present invention.
FIG. 1 is a schematic flowchart of a coal briquette manufacturing
method according to an exemplary embodiment of the present invention. The
flowchart of the coal briquette manufacturing method illustrated in FIG. 1 is
merely for exemplifying the present invention, and the present invention is not
15 limited thereto. Thus, a method for manufacturing coal briquettes can be
variously modified.
As shown in FIG. 1, the coal briquette manufacturing method includes
providing a mixture of a raw coal and a binder (S10), coating an endothermic
material to surfaces of a pair of molding rolls applied to mold the mixture (S20),
20 and charging the mixture between the pair of molding rolls and providing coal
briquettes coated with the endothermic material by compression-molding the
mixture through the pair of molding rolls (S30). The coal briquette
manufacturing method may further include other processes.
First, in S10, a mixture of a raw coal and a binder is provided. As the
7
raw coal, a fine coal may be used. In order to reduce quality deviation, fine
coals should preferably have uniform grain size, and specifically, fine coal
having a grain size distribution in which a grain size of 5 mm or less is 90 wt%
to 100 wt% may be used.
The amount of moisture mixed into the fine 5 ine coal may be maintained to
be about 2 wt% to 12 wt%. When the amount of moisture mixed into the fine
coal is controlled within the above-stated range, moisture can efficiently block
pores of particles of fine coal. Accordingly, since the binder with the particles
of fine coal cannot be permeated into the fine coal particles and thus exists at
10 the outside of the fine coal particles, the fine coal particles can be well bound
with each other, thereby efficiently enhancing hot strength and cold strength of
the coal briquettes. As the binder, molasses, raw sugar, cellulose, starch,
bitumen, and the like may be used. The amount of binder may be 3 wt% to 15
wt% of the mixture. When the amount of binder is too small, strength of the
15 coal briquettes may be weakened. On the contrary, when the amount of
binder is too high compared to the amount of the mixture, a problem such as
attachment may occur in mixing of the fine coal and the binder. Thus, the
amount of binder is controlled within the above-stated range.
The mixture may further include a hardening agent at 1 wt% to 5 wt%.
20 As the hardening agent, quicklime, slaked lime, calcium carbonate, cement,
bentonite, silica, limestone, and the like may be used. When the amount of the
hardening agent is too small compared to the amount of the mixture, insufficient
chemical binding occurs between the binder and the hardening agent so that
the coal briquettes may have insufficient strength. However, when the amount
8
of the hardening agent is too large compared to the amount of the mixture, ash
content in the coal briquettes is increased and thus coal briquettes may not play
a sufficient role as a fuel in the melter-gasifier. Accordingly, the amount of the
hardening agent needs to be appropriately controlled. When molasses is used
as the binder and quicklime or slaked lime is used as the hardening 5 ing agent, it is
preferred to uniformly mix the hardening agent into the fine coat first and then
add the molasses. In this case, cold strength of the coal briquettes
manufactured in the next process can be improved by binding of calcium
saccharate.
10 Referring back to FIG. 1, an endothermic material is coated to the
surfaces of the pair of molding rolls that shape the mixture in S20. Here, as
the endothermic material, a metal hydroxide, limestone, or dolomite may be
used. As the metal hydroxide, aluminum hydroxide or magnesium hydroxide
may be used. The endothermic material is coated to the surface of the coal
15 briquettes in S30. When the coal briquettes are charged into the meltergasifier
and then undergo a reaction, the endothermic material coated on the
surface of the coal briquettes causes an endothermic reaction and thus the
surface of the coal briquettes develops local low-temperature regions. Thus, a
grain diameter of char is increased by lowering a reaction temperature, the
20 number of surface cracks is decreased, and the amount of char separated from
the unit coal briquettes is decreased. This will be described in detail with
reference to FIG. 2.
The coal briquettes are charged into the melter-gasifier and thermally
decomposed in an upper portion of a char bed by a high-temperature gas rising
9
from a lower portion of the melter-gasifier. In this case, a temperature of the
high-temperature gas that causes thermal decomposition of the coal briquettes
highly affects the surface shape and mean grain diameter of the char of the coal
briquettes.
FIG. 2 shows photos of the surface shape of 5 f the coal briquette where
char is formed in cases that temperatures of the high-temperature gas are
respectively 900 °C, 1000 °C, and 1100 °C. In FIG. 2, (a) is a photo of the
surface of coal briquettes where char is formed at 900 °C, (b) is a photo of the
surface of coal briquettes where char is formed at 1000 °C, and (c) is a photo of
10 the surface of coal briquettes where char is formed at 1100 °C.
As shown in FIG. 2, the grain diameter of the char is increased as the
reaction temperature is lower. Further, the number of surface cracks is
reduced and the amount of char separated from unit coal briquettes is reduced.
Since the coal briquettes according to the exemplary embodiment of the
15 present invention are coated with the endothermic material at the surface
thereof, when the coal briquettes are charged into the melter-gasifier, the
endothermic material causes an endothermic reaction such that the surface of
the coal briquettes develops local low-temperature regions. Thus, the reaction
temperature of the coal briquettes is lowered such that the grain diameter of the
20 char is increased, the number of cracks is reduced, and the amount of char
separated from unit coal briquettes is reduced.
The aluminum hydroxide, which is an endothermic material, experiences
an endothermic reaction and a dehydration reaction at 180 °C to 220 °C, and
magnesium hydroxide experiences an endothermic reaction and a dehydration
10
reaction at about 330 °C. Further, limestone experiences a burning reaction
and an endothermic reaction at about 900 °C, and dolomite experiences a
primary burning reaction and an endothermic reaction at 650 °C to 750 °C and a
secondary burning reaction and an endothermic reaction at about 900 °C. The
surface of the coal briquettes can be locally low-5 -temperature through such an
endothermic reaction.
When the endothermic material is coated, the surfaces of the pair of
molding rolls are maintained at room temperature. In further detail, the surface
temperature of the pair of molding rolls may be maintained at 20 °C to 30 °C.
10 More preferably, the surface temperature of the pair of molding rolls may be
maintained at about 25 °C. When the surface temperature of the molding rolls
is too high, the endothermic material may be evaporated before being coated to
the surface of the coal briquettes.
In S30, the mixture is charged between the pair or molding rolls, and the
15 mixture is compression-molded by the pair of molding rolls such that coal
briquettes coated with the endothermic material are manufactured. In this
case, the amount of coated endothermic material may be about 3 wt% to 15
wt% of each coat briquette. When the amount of endothermic material is too
small, the coal briquettes are penetrated into the melter-gasifier and thus easily
20 differentiated. Further, when the amount of endothermic material is too large,
the endothermic material cannot be easily coated to the coal briquettes and
thus remains at the outside of the coal briquette. Accordingly, the amount of
endothermic material is controlled to be included in the above-stated range. In
further detail, the amount of endothermic material may be 4 wt% to 8 wt%.
11
FIG. 3 schematically illustrates a molding device 100 for manufacturing
the coal briquettes of the method of FIG. 1. FIG. 3 partially illustrates molding
rolls 11 and 12, and other parts of the molding rolls are omitted for convenience
of description.
The mixture is charged between the pair of molding rolls 5 olls 11 and 12
coated with an endothermic material 10. The endothermic material 10 is
coated to concave grooves 111 and 121 of the pair of molding rolls 11 and 12.
Thus, the mixture is compression-molded by the pair of molding rolls 11 and 12
such that coal briquettes coated with the endothermic material 10 can be
10 manufactured. Since pressure is appropriately applied to the mixture by the
pair of molding rolls 11 and 12 for compression of the mixture, the surface of the
coal briquettes can be well coated with the endothermic material 10.
FIG. 4 schematically illustrates a cross-sectional structure of the molding
device 100 of FIG. 3, taken along the line IV-IV. More specifically, FIG. 4
15 illustrates a process for manufacturing coal briquettes coated with the
endothermic material 10 by the molding device 100.
As shown in FIG. 4, the endothermic material 10 is sprayed through
nozzles provided above the pair of molding rolls 11 and 12. Thus, the
endothermic material 10 is coated to the concave grooves 111 and 121 of the
20 pair of molding rolls 11 and 12 that rotate in opposite directions to each other.
The pair of molding rolls 11 and 12 compress and shape the mixture
charged therebetween. Thus, the surfaces of coal briquettes compressed by
the pair of molding rolls 11 and 12 are uniformly coated with the endothermic
material 10. Thus, the coal briquettes coated with the endothermic material 10
12
can be manufactured.
FIG. 5 schematically illustrates a molten iron manufacturing device 200
using the coal briquettes manufactured in the method of FIG. 1. A structure of
the molten iron manufacturing device 200 illustrated in FIG. 5 is merely for
exemplifying the present invention, and the present invention 5 ion is not limited
thereto. Thus, the shape of the molten iron manufacturing device 200 of FIG.
5 can be variously modified.
As shown in FIG. 6, the molten iron manufacturing device 200 includes
a melter-gasifier 210, a plurality of fluidized-bed reduction furnaces 222, a
10 reduced iron compressor 240, and a compression reduced iron storage
container 250. The compression reduced iron storage container 250 may be
omitted.
The manufactured coal briquettes are charged into the melter-gasifier
210 and form a coal-packed bed in the melter-gasifier 210. Here, the coal
15 briquettes cause generation of a reduction gas in the melter-gasifier 210, and
the reduction gas is supplied to the fluidized-bed reduction furnaces 222. Fine
iron ores are supplied to the plurality of fluidized-bed reduction furnaces 222
having fluidized beds, and are fluidized by the reduction gas supplied to the
fluidized-bed reduction furnaces 222 from the melter-gasifier 210 such that
20 reduced iron is manufactured. The reduced iron is compressed by the reduced
iron compressor 240 and then stored in the compression reduced iron storage
container 250. The compressed reduced iron is supplied to the melter-gasifier
210 from the compression reduced iron storage container 250 and then melted
in the melter-gasifier 210.
13
A dome portion 201 is provided in an upper portion of the melter-gasifier
210. That is, a space wider than other portions of the melter-gasifier 210 is
formed, and a high-temperature reduction gas exists in the space. Thus, the
coal briquettes charged into the dome portion 201 can be easily differentiated
by the high-temperature reduction gas. That is, since the coal briquettes 5 iquettes are
charged into an upper portion of the melter-gasifier 210 maintained at a
temperature of about 1000 °C, the coal briquettes receive sudden heat impact.
Accordingly, the coal briquette can be differentiated while moving downward in
the melter-gasifier 210.
10 However, the coal briquettes manufactured by the method of FIG. 1 are
coated with the endothermic material, and therefore a temperature of the
surface of the coal briquette can be locally reduced through an endothermic
reaction of the endothermic material. Thus, the coal briquettes drop to the
lower portion of the melter-gasifier 210 rather than being differentiated in the
15 dome portion 201 of the melter-gasifier 210. Char formed from thermal
decomposition of the coal briquette moves to a lower portion of the meltergasifier
210 and undergoes an exothermic reaction with oxygen supplied
through a tuyere 230. Thus, the coal briquettes can be used as a heat source
that keeps the melter-gasifier 210 at a high temperature. Meanwhile, since
20 char provides ventilation, a large amount of gas generated from the lower
portion of the melter-gasifier 210 and reduced iron supplied from the fluidizedbed
reduction furnace 222 can more easily and uniformly pass through the coalpacked
bed in the melter-gasifier 210.
In addition to the above-stated coal briquettes, lump carbon ash or coke
14
may be charged into the melter-gasifier 210, as necessary. The tuyere 230 is
provided in an outer wall of the melter-gasifier 210 for injection of oxygen.
Oxygen is injected into the coal-packed bed such that a combustion zone is
formed. The coal briquettes may be burned in the combustion zone to
5 generate the reduction gas.
FIG. 6 schematically illustrates another molten iron manufacturing
device 300 using the coal briquettes manufactured in the method of FIG. 1. A
structure of the molten iron manufacturing device 300 illustrated in FIG. 6 is
merely for exemplifying the present invention, and the present invention is not
10 limited thereto. Thus, the shape of the molten iron manufacturing device 300
of FIG. 6 can be variously modified. The structure of the molten iron
manufacturing device 300 of FIG. 6 is similar to the structure of the molten iron
manufacturing device 200 of FIG. 5, and therefore like reference numerals are
used for like parts, and the detailed description is omitted.
15 The molten iron manufacturing device 300 of FIG. 6 includes a meltergasifier
210 and a plurality of packed-bed reduction furnaces 222. The molten
iron manufacturing device 300 may include other devices as necessary. Iron
ore is charged into the plurality of packed-bed reduction furnaces 220 and then
reduced. The iron ore charged into each packed-bed reduction furnace 220 is
20 dried in advance and then passed through the packed-bed reduction furnace
220 such that reduced iron is manufactured. The packed-bed reduction
furnace 220 receives the reduction gas from the melter-gasifier 210 and thus
forms a packed bed therein.
Hereinafter, the present invention will be described in further detail with
15
reference to experimental examples. The experimental examples are used
only to illustrate the present invention, and are not meant to be restrictive.
Experimental Example 1
Coal A having an average phase and a grain size of 5 mm or less was
prepared as a raw coal. Characteristics of coal A used in Experim5 ental
Example 1 are shown in Table 1.
(Table 1)
Technical analysis, dry base wt%
Ash Volatile matter (VM) Fixed carbon
Coal A 9.1 25.1 65.8
As a binder, molasses at 8 wt% was added, and the coal A and
molasses were uniformly mixed. As an endothermic material, limestone at 6.2
10 wt% of the coal briquettes was coated to the surfaces of a pair of molding rolls.
The mixture of the coal A and molasses was charged into the pair of molding
rolls that were coated with the endothermic material and compressed such that
100 wt% of coal briquettes was manufactured in the shape of a 64.5 mm X 25.4
mm X 19.1 mm sized pillows.
15 Experimental Example 2
As an endothermic material, 6.5 wt% of dolomite was coated to the
surface of a pair of molding rolls. The rest of the experiment process was the
same as that of Experimental Example 1.
Comparative Example 1
20 An endothermic material was not coated to the surface of a pair of
molding rolls. The rest of the experiment process was the same as that of
16
Experimental Example 1.
Comparative Example 2
As a hardening agent, 2 wt% of limestone was added to a mixture of
coal A and molasses, and an endothermic material was not coated to the
surface of a pair of molding rolls. The rest of the experiment process was 5 as the
same as that of Experimental Example 1.
EXPERIMENT FOR EVALUATION OF PHYSICAL CHARACTERISTICS OF
COAL BRIQUETTE
In order to evaluate coal briquettes manufactured according to the
10 above-stated Experimental Example 1, Experimental Example 2, Comparative
Example 1, and Comparative Example 2, one coal briquette was charged into a
fast heating furnace maintained at a 1000 °C temperature and underwent heat
treatment for 15 min and thus char was acquired. Table 2 shows a ratio of a
total number of particles of the acquired char, each having a grain diameter of
15 13 mm or more.
(Table 2)
Endothermic material
(wt%)
Total number of
particles
(number/coal
briquette)
Ratio of particles
having grain diameter
of 13 mm or more (%)
Experimental
Example 1
limestone
6.2 wt%
18 33.3
Experimental dolomite 17 47.1
17
Example 2 6.5 wt%
Comparative
Example 1
- 22 27.3
Comparative
Example 2
- 21 28.4
As shown in Table 2, a total number of particles of char generated from
a coal briquette manufactured according to Experimental Example 1 was
reduced compared to a total number of particles of char generated from a coal
briquette manufactured according to Comparative Example 1 and Comparative
Example 2, and a ratio of particles, each having a grain diameter 5 eter of 13 mm or
more, was increased. Further, a total number of particles of char generated
from a coal briquette manufactured according to Experimental Example 2 was
reduced compared to the total number of particles of char manufactured
according to the coal briquette manufactured according to the comparative
10 examples, and a ratio of particles, each having a grain diameter of 13 mm or
more, was increased.
As described, the coal briquette according to the exemplary embodiment
of the present invention is not easily differentiated in a melter-gasifier,
combustion heat for melting of reduced iron can be sufficiently provided,
15 thereby saving fuel cost, and ventilation in the melter-gasifier can be improved.
While this invention has been described in connection with what is
presently considered to be practical exemplary embodiments, it is to be
understood that the invention is not limited to the disclosed embodiments, but,
on the contrary, is intended to cover various modifications and equivalent
18
arrangements included within the spirit and scope of the appended claims.

10. endothermic material
11. 12. molding roll
111. 121. 5 . concave groove
100. molding device
210. melter-gasifier
220. packed-bed reduction furnace
222. fluidized-bed reduction furnace
10 230. tuyere
240. reduced iron compressor
250. compression reduced iron storage container
200, 300. molten iron manufacturing device
201. dorm portion

WHAT IS CLAIMED IS:
1. A method for manufacturing coal briquettes in a molten iron
manufacturing device including a melter-gasifier into which reduced iron is
charged and a reduction furnace connected to the melter-5 gasifier and providing
reduced iron, the coal briquettes being charged into a dome portion of the
melter-gasifier and rapidly heated, the method comprising:
providing a mixture of raw coal and a binder;
coating an endothermic material to the surface of a pair of molding rolls
10 applied to mold the mixture; and
providing coal briquettes coated with the endothermic material by
charging the mixture between the pair of molding rolls and compressionmolding
the mixture with the pair of molding rolls,
wherein in the coating of the endothermic material, the endothermic
15 material is selected from a group consisting of a metal hydroxide, limestone,
and dolomite.
2. The method for manufacturing coal briquettes of claim 1,
wherein the amount of endothermic material is 3 wt% to 15 wt% of the coal
20 briquettes.
3. The method for manufacturing coal briquettes of claim 2,
wherein the amount of the endothermic material is 4 wt% to 8 wt% of the coal
briquettes.
20
4. The method for manufacturing coal briquettes of claim 1,
wherein, in the providing of the mixture, the binder is a material selected from a
group consisting of molasses, raw sugar, cellulose, starch, and bitumen.
5
5. The method for manufacturing coal briquettes of claim 1,
wherein, in the providing of the mixture, the amount of powdered coal having a
grain diameter of 5 mm or less included in the raw coal is 90 wt% to 100 wt%.
6. The method for manufacturing coal briquettes of 10 f claim 1,
wherein, in the coating of the endothermic material, the surface of the pair of
molding rolls is maintained at room temperature.
7. The method for manufacturing coal briquettes of claim 1,
15 wherein, in the providing of the mixture, the mixture comprises a binder at 3
wt% to 15 wt% and raw coal as the remaining portion of the mixture.
8. Coal briquettes provided to a molten iron manufacturing device
including a melter-gasifier to which reduced iron is charged and a reduction
20 furnace connected to the melter-gasifier and providing reduced iron, wherein
the coal briquettes are charged into a dome portion of the melter-gasifier and
rapidly heated therein, and wherein the coal briquettes comprise:
a mixture of raw coal and a binder; and
an endothermic material coated to the mixture,
21
wherein the endothermic material is a material selected from a group
consisting of a metal hydroxide, limestone, and dolomite.
9. The coal briquettes of claim 8, wherein the amount of
endothermic material is 3 wt% to 15 wt% of the coal 5 l briquettes.
10. The coal briquettes of claim 9, wherein the amount of
endothermic material is 4 wt% to 8 wt% of the coal briquettes.
10 11. The coal briquettes of claim 8, wherein the mixture comprises a
binder at 3 wt% to 15 wt% and raw coal as the remaining portion of the mixture.